Shepard Fairey’s Barack Obama posters were the defining image of the presidential campaign.

The high-contrast red, white and blue portrait went viral overnight, appearing on everything from posters to T-shirts to the cover of Time magazine, and catapulting the Los Angeles-based graphic designer and street artist from subversive propagandist to mainstream icon.

On Saturday, in a gala reception featuring senators, congressmen and governors, the underground artist’s iconic portrait was unveiled at the Smithsonian’s National Portrait Gallery in Washington, D.C., alongside more traditional paintings of George Washington, Abraham Lincoln and Ronald Reagan.

So what happens when a punk rock, culture-crashing artist with an anti-establishment streak and a healthy arrest record gets invited to the party? Maybe he mellows … just a bit.

“The whole idea that ‘underground is good and government is bad’ is a very one-dimensional idea,” Fairey said, standing in front of a brand-new, 16-by-6 painting of the soon-to-be-president at his traveling “Manifest Hope: DC Gallery” in Georgetown.

“It’s really about taking the opportunity to make the system what we can make it — as progressive, forward-thinking people — and raising the bar for everyone.

“Still, to think that I was standing there with a piece of art that was created as illegal street art to support a campaign no one even thought really had a chance at the time seemed like a real coup to me.”

Ultimately, Fairey said, the ubiquity of his “Hope” poster campaign demonstrates the power of individual inspiration.

“This is a perfect example of how an individual can inspire other individuals and, the next thing you know, something that came from a real, pure place without any secondary motivations that were monetary or based on power can actually influence things.

“I think a lot of people think that the people who hold the strings have it all sewn up, and there’s no point in acting. So the thing that inspires me the most about this validation in the National Portrait Gallery is that it’s proof that it doesn’t have to be this way.”